i have ideas for a vampire oc but dont know how to go about it

I long to portray the agony of being an immortal being.
I must put across the empty abyss that takes over, filling every inch of her ever-growing abode.
To spend centuries rotting in her own misery, chipping away at her sanity.

The walls of her home only serve to suffocate; however big they could possibly be, they would never be large enough to let her flee from it. The farther she wondered, the bigger they seemed to be.

The only time she could ever let herself escape from her self-inflicted prison was when the hunger took over. The burning, betraying starvation that took over in her weakest moments, when her cheeks were hollow and the only thing repeating in her head would be the screaming for her to feed, distracting her from the only other thing she felt.

The only other thing she felt was gut-wrenching loneliness and self-hatred.

When she did finally feed -as she was destined to do- she would be forced to witness the sight of herself gnawing on the flesh of a desperate human being, it no longer being a simple bite in the neck. The innocence flashing through their face as their eyes shine in their last fleeting moments.

Afterwards... she would be stuck with the aftermath, all that was left once that feeling of hunger was gone was the immense disappointment, the knowledge that another life had been taken by her very own hands once again. 

Again and again, over and over and over, she was stuck in that horrible loop without even the hopes of savior or even the relief of death.

She didn't even dream about savior anymore. She didn't think she was deserving of such a noble thing to happen to a creature such as her, so all she could do was dream of death.

And oh, how she longed for it. Death to come and save her from the torture, to set her free, to put her out of her misery. How many decades had it been? Centuries even? It didn't matter anymore.

She never seems to be aware that this entrapment is entirely of her own doing.

She needs to save herself, for no one can do it for her.